1. Field of the Invention
The present invention relates in general to vehicle engines and, in particular, to an air intake manifold and a composite flange assembly or structure for use with the air intake manifold and vehicle engines, generally.
2. Description of Related Art
An air intake manifold assembly of a multi-cylinder engine typically includes a plurality of branched air passageways or ducts. Each of the air passageways defines a generally tubular-shaped runner having an air intake port and an opposing air inlet port. The air intake port of the runner is connected to an associated plenum that supplies atmospheric, turbo, or supercharged air to the runner air intake port. The air inlet port is connected to a flange that is connected to an associated air inlet port of each cylinder of the engine to supply the air from the runner to each cylinder. Conventional air intake manifold assemblies are typically constructed of cast iron, magnesium, aluminum, and plastic.
A typical aluminum air intake manifold assembly is produced by conventional casting processes. These manifolds typically include a plurality of tubes arranged having one end connected with the outlet holes of an air intake plenum, and opposing ends connected with the associated holes of a flange member which is adapted for mounting to a cylinder head of an engine. The tubes may be U-shaped to fit conveniently in the allowed space and as such the manifold cannot typically be cast in one piece but rather must be cast in multiple sections, for example in two sections. One section includes a length of the tubing cast integrally with the plenum and the other section includes the remaining length of the tubing cast integrally with the flange member. This manifold configuration allows adequate access to the mounting features of the manifold. The halves must then be joined together with bolts and a gasket or other suitable hardware to complete the manifold, further adding to the cost and complexity of the manifold. In like manner, the lack of access to some mounting fasteners may require the manifold to be made of a very stiff material to allow the elimination of the occluded fasteners.
A typical plastic manifold maybe formed as one piece or in multiple pieces. Plastic manifolds may be produced using injection molding or blow molding processes. Subsequent secondary operations then create a hollow structure for fluid communications of air into the inlet ports of the cylinder head. A typical plastic multi-piece manifold assembly may include an upper half shell and a lower half shell which are joined together by a welding process to create a hollow structure. In some instances, the plastic multi-piece manifold assembly includes one or more inner shell pieces that are disposed within the upper and/or lower half shells. The inner shell may be lower partial inserts that are secured to the lower half shell, upper partial inserts which are secured to the upper half shell, or both lower and upper partial inserts which are secured to the respective lower and upper half shells. The inserts are typically joined to the associated half shell by a conventional heat staking process or welding process. In some instances, a plurality of individual tubes are disposed within the upper and lower half shells and joined thereto by a conventional heat staking or welding process. In both types of constructions, the inserts or the inserts in cooperation with upper or lower half shells define a corresponding number of runner paths through which air is supplied to the associated cylinder head of the engine.
The conventional metal components typically used within air intake manifold assemblies are heavier and costlier than desirable. Consequently, with requirements for reduced weight and improved performance of vehicle engines, a need exists to form more engine components from plastic and/or composite materials. Also, with an emphasis on cost and reliability, it is desirable to reduce the number of parts needed to form an assembly and to reduce the service costs by minimizing the time and tools needed for servicing. While plastic and composite materials are in use for some vehicle components, plastics and composites are generally not as strong (i.e., stiff) as conventional metals. Generally, conventional metal components have no difficulty achieving desired strength (i.e., stiffness) requirements, but plastics and composites, in general, do not traditionally perform as well as conventional metal components for sealing and mounting functions.
Thus, it is desirable to provide an air intake manifold assembly that improves weight, cost, and complexity concerns as compared with conventional metal assemblies, but performs equally as well in the air flow metering function and local stiffness for mounting and sealing of the conventional assemblies.